Effects of dietary rape seed oil, copper(II) sulphate and vitamin E on drip loss, colour and lipid oxidation of chilled pork chops packed in atmospheric air or in a high oxygen atmosphere

The effect of addition of rapeseed oil (canola), CuSO4 and vitamin E (all-rac-alpha-tocopheryl acetate) to pig diets on pork meat quality (lipid oxidation, colour and drip loss) was studied. Pigs were reared on ten different diets, either a control diet (no supplementation of rapeseed oil, CuSO4 or vitamin E) or 6% rapeseed oil diets supplemented with CuSO4 (0, 35 or 175 mg/kg) and vitamin E (0, 100 or 200 mg all-rac-alpha-tocopheryl acetate/kg). The natural content of vitamin E originating from feed ingredients amounted to 9-23 mg vitamin E (alpha-tocopherol) per kg feed. Muscle vitamin E levels reflected the dietary intake and pigs fed the control diet had significantly lower levels than pigs fed rapeseed oil diets. The quality of fresh pork chops packed in air or in 80% O-2:20% CO2 was followed during chill storage for 8 and 13 days, respectively. Colour, as measured by tristimulus colorimetry of pork chops packed in 80% oxygen atmosphere, was significantly improved with respect to redness when compared to chops packed in air, regardless of dietary treatment. The low vitamin E content in pigs fed the control feed significantly decreased a values and the oxidative stability of pork chops during chill storage compared to the other feeding groups. Packing of chops in a high-oxygen atmosphere increased lipid oxidation, especially in chops with low levels of vitamin E. Supplementation of rapeseed oil diets with 100 or 200 mg vitamin E significantly decreased lipid oxidation of chill stored chops. Supplementation with CuSO4 did not influence meat quality attributes (drip loss, colour stability and lipid oxidation) for any of the storage conditions. (C) 1998 Elsevier Science Ltd. All rights reserved